PTL 1 discloses a chuck device that is provided with an exchangeable fitting body (chuck portion) according to the type of workpiece. The fitting body is disposed to be attachable to and detachable from a chuck base. When the fitting body is detached from the chuck base, a first cylinder device and a second cylinder device are used to separate the fitting body from the chuck base. When the fitting body is attached to the chuck base, a disc spring is used to cause the fitting body to approach the chuck base. Note that, biasing force (elastic restoring force) of the disc spring is accumulated in the disc spring by driving the first cylinder device when the fitting body is detached from the chuck base.